blocking circumventor pages

[jamie-a]

I`m trying to get our bloxx unit to block circumventor sites, They all have the same text so I hoped blocking the paragraph about censorship and signing up for email updates would block them but it doesnt seem to work, looking at the html code this all seems to be encrypted which makes me wonder if this is why it not getting blocked.

 

Has anyone had any look blanket blocking all these?

[maf_001]

Hi,

 

I managed to filter all the proxy bypass sites using ISA 2006, the easiest way is to filter all Https traffic. Then just have an allowed list for the trusted sites that they need Https to. I found that the pupils didnt need access to that many Https sites.

 

I am not the biggest fan of bulk blocking when it comes to filtering, but this way worked for me.

 

Mark

[jamie-a]

Thanks but unfortuantley these are not always https sites, delving deeper in the page source reveals its created in java script with each word broken up into chunks of 2 and 3 characters with a random zero length string placed in between them. The chunks are broken up in a different way each time the site is accessed otherwise I could have given 10 chunks 20 or so points and blocked the page if 200 point was reached.

[tom_newton]

Jamie,

 

There are a lot of different ways proxy authors try to disguise their evil ways. Keeping on top of these is a full time job (in fact we have folk whose full time job it is to do this!). Certainly you can look at reconstructing the javascript code but it is fairly tough to do, and they don't always say "proxy" on em in inch high lettering!

 

Edit: bear in mind that a number of the non-https ones will also function https - where most content filters will fail.

 

Tom